what causes cyclinders to be washed with gasoline on 1990 Mercedes-Benz 560SEL

left bank side only

The injector circuit on that cylinder bank may be shorted to ground opening all the injectors and washing the cylinders with fuel. Do not create sparks testing the injector circuit if there's fuel present.
This is dangerous to deal with, be aware that you can get a lot of fuel in the exhaust and in the motor oil creating a fire and explosion hazard. When you are working on the car, disable the ignition until you can be sure that there isn't a fuel liquid or vapor hazard.
1988 560 sel no compression was found on left bank all cyclinders ,inspected timing chain& valvetrain operation ok, squirted a little oil in cylinders vehicle tries to start but will not, cylinder leak test performed no air leaks found ,,,stuck !!!!